Troffer construction for combination ventilating and illuminating units



3,045,577 ING July 24, 1962 H. M. LAZERSON TROFFER CONSTRUCTION FOR COMBINATION VENTILAT AND ILLUMINATING UNITS 5 Sheets-Sheet 1 Filed July 12, 1961 INVENTOR. HERMAN M. L AZERSON July 24, 1962 H. TROFFER CONSTRUCTION FOR COMBINATION VENTILATING Filed July 12, 1961 M. LAZERSON AND ILLUMINATING UNITS 3 Sheets-Sheet 3 INVENTOR. HERMAN M. LAZERSON BY fiwg 4 HEB/5- United States Patent 3,045,577 TROFFER CONSTRUCTION FOR COMBINATION VENTILATING A'Nl) ILLUMINATING UNITS Herman M. Lazerson, Chicago, Ill., assignor to Solar Light Manufacturing Co., Chicago, Ill., a corporation of Illinois Filed July 12, 1961, Ser. No. 123,511 3 Claims. (Cl. 984t The present invention relates generally to combination ventilating and illuminating units and more particularly to a troffer for such a unit which troft'er is sturdy, compact, vibration-resistant, and relatively light in weight.

Basically, the subject trotfer is ceiling-mounted and comprises an inverted trough-shaped outer shell having a pair of open ends, an inverted trough-shaped inner shell having open ends and disposed in nesting relation to the outer shell, spacing members extending between the nested shells, the adjacent side surfaces of the spaced nested shells defining a pair of downwardly extending air passages, and a pair of end plates each covering a respective opposite open end of the shells.

The spacing members are located and constructed in a manner to be subsequently described, providing a minimum of obstruction and restriction to the flow of air through the troifer passages, thus minimizing air turbulence within the passages and accordingly reducing the vibrations caused thereby. The subject troffer is also characterized by a compact bracing arrangement integral with the end plates, which further increases sturdiness and vibration-resistant properties of the troifer. In addition, the troifer contains a minimum number of parts and hence Weighs less, an important consideration in any ceiling-supported installation, while also reducing material costs and the time and expense of fabricating and assembling the troffer.

Therefore, a primary object of the present invention is to provide a troifer for a combination ventilating and illuminating unit which troffer is compact, sturdy, and vibration-resistant. Another object is to provide a troffer of the type described which is comparatively light in weight and economical to manufacture.

Still another object of the invention is to orient the air flow from the troffer through its discharge ports such that localized downdrafts are avoided, thereby to improve room comfort and ventilation.

Other objects and advantages inherent in the structure disclosed and claimed will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 is a fragmentary perspective view from below of a room ceiling with a ventilating and illuminating unit containing the subject troffer mounted within an opening in the ceiling;

FIG. 2 is an exploded perspective view of a unit including the troffer;

FIG. 3 is a side elevational view of the unit;

FIG. 4 is an enlarged sectional view taken along the line 44 in FIG. 3;

FIG. 5 is a sectional view taken along the line 5--5 in FIG. 4, showing both ends of the troifer in fragmentary relation;

FIG. 6 is a sectional view taken along the line 6-6 in FIG. 4, showing both ends of the trotfer in fragmentary relation;

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FIG. 7 is a transverse sectional view of FIG. 6, showing the hinge and latch means for the lower panel;

FIG. 8 is a fragmentary perspective view, partially cut away, of a lower corner of the trotfer.

With reference initially to FIGS. 1 and 2, there is shown a combination ventilating and illuminating unit 10 comprising a troffer indicated generally at 15, said trofier having an outer shell 20 and an inner shell 21 maintained in nested spaced relation to the outer shell by spacing members to be described subsequently. Each of the shells 20, 21 has an inverted trough-shaped configuration and open ends, said ends being closed by end plates 22.

Outer shell 20 has an upper opening (not shown) for receiving a conventionally constructed air supply and damper box indicated generally at 16 (FIG. 2), and inner shell 21 contains a lighting element in the form of fluorescent tubes 17 carried by tube sockets 13 mounted on the inner shell by conventional means (FIG. 4). A ballast 14 is electrically connected to fluorescent tubes 17 through tube sockets 13 in a well-known manner, and a source of electrical energy (not shown) is also electrically connected to the ballast and tube socket whereby the lighting elements may be energized. As may be seen in FIG. 4, a reflector that also acts as a separator, indicated generally at 18, is located within inner shell 21 in spaced relation to top wall 36 thereof and in proximate relation to inclined portions 37 and 38 thereof between the top wall and fluorescent tubes 17. Reflector or separator 18 functions to reflect both visible and invisible radiant energy downwardly and away from air chamber 12, and the separator 18 further serves to physically isolate the environs adjacent the fluorescent tubes 17 from the environs between top wall 36 and the separator 18. Thus, an insulating layer of relatively static air is formed between top wall wall 36 and separator 18 whereby heat transfer is minimized between air chamber 12 and fluorescent tubes 17.

Closing the bottom of the unit 10 is a lower panel or plate indicated generally at 19. As shown in FIGS. 1 and 3, unit 10 is normally installed within an opening in a ceiling 11 of a room with lower panel 19 flush with the lower surface of the ceiling.

For a more detailed description, reference is made to FIGS. 4, 5 and 6, wherein outer shell 20 is shown to comprise a top wall 25 from which extend opposite side walls comprising respective first inclined portions 26, 27, each connected to a downwardly extending vertical portion 28, 29, each connected to a second inclined portion 30, 31, each connected to an outwardly extending flange 32, 33, each terminating in a respective upright portion 34, 35. Inner shell 21 comprises a top wall 36 from which extend opposite side Walls each comprising a respective inclined portion 37, 38, each connected to a downwardly extending vertical portion 39, 40, each connected to an outwardly extending horizontal flange 41, 42, each coplanar with but terminating short of corresponding flanges 33, 32 on the outer shell to provide air outlets 43.

It is thus apparent (see FIG. 4) that the unique arrangement of the outer and inner shells 20, 21, with respectively oriented portions 26, 28, 3t), and 32 in the outer shell and 37, 39, and 41 in the inner shell on the right side, and with corresponding portions 27, 29, 31, and 33 in the outer shell and 38, 40, and 42 in the inner shell on the left side, define vertically facing air outlets 4.3 through which the air is directed from the troffer obliquely from the vertical. The flanges 41, 42 while preventing a vertical downdraft by directing the air flow along the inclined portions 30, 31 also create turbulence points P in the air stream to further minimize any direct vertical downdraft. This construction avoids discomfort in the room occasioned by downdrafts impinging upon occupants thereof. Moreover, the unique arrangement provides for an improved ventilation and overall temperature gradient in the room of use, since the ventilating air is obliquely directed toward the upper portions of the rooms atmosphere, which portions are consequently set into turbulence and de-stagnated.

Extending between outer shell top wall 25 and inner shell top wall 36 are a pair of channel-shaped spacing members 45, each located at a respective opposite end of the troffer (FIG. Extending between the side walls of the inner and outer shells at each lower corner of the troffer, and also at the mid-portion thereof, is a Z-shaped spacing member 46 (FIGS. 4 and 6). Spaced top walls 25, 36 define an air chamber 12 (FIG. 5) which receives air from air supply and damper box 16 and communicates with a pair of downwardly and outwardly extending air passages 23, 24 (FIGS. 4 and 6), defined by the spaced side walls of the two nested shells 20, 21 and terminating at their outlets 43 (FIG. 5), which are normally flush with ceiling 11 when the unit is in an installed position (FIG. 1).

With reference to FIG. 8, each Z-shaped spacing member 46 is shown to comprise a first flange 47 abutting inner shell vertical portion 39, a second flange 48 abutting outer shell vertical portion 29, and a web 49 extending between flanges 47 and 48. As further shown in FIG. 8, flange 47 has upper and lower extremities 50, 52 respectively, which extend no further than upper and lower extremities 51, 53 of inner shell vertical portion 39. Similarly, second flange 48 has upper and lower extremities 54, 56, which extend no further than upper and lower extremities 55, 57 of outer shell vertical portion 29. In addition, web 49 extends substantially perpendicularly to vertical portions 39 and 29 of the inner and outer shells, respectively. By virtue of this construction, flanges 47, 48 and web 49 offer minimum obstruction to the flow of air through air passages 23, 24 with a corresponding minimization of air turbulence within the trofler and vibration thereof.

More specifically, if first flange 47 extended above upper extremity 51 of inner shell vertical portion 39, or if second flange 48 extended below lower extremity 57 of outer shell vertical portion 29, these flanges would be directly in the path of air flowing through passage 23 toward air outlet 43 and would deflect this air thereby causing turbulence and vibration. Similarly, if web 49 were inclined other than perpendicularly to vertical portions 29, 39, the web would be disposed more nearly broadside to the flow of air toward air outlet 43 instead of edgewise as in the subject construction; such a broadside disposition would be substantially more obstructive to the flow of air with a resulting increase in air turbulence and troffer vibration.

Z-shaped spacing members 46 and channel-shaped spacing member 45 are preferably welded to shells 20, 21 and serve to rigidify the trofler; in this manner vibration caused by the flow of air through chamber 12 and passages 23, 24 is further minimized.

As seen in FIG. 2, each end plate 22 has a configuration following the cross-sectional configuration of outer shell 20, and an inwardly extending peripheral flange 60 which overlaps the outer shell 20. Near the bottom of each end plate 22 is an inwardly extending portion 61 characterized by an L-shaped cross-section. Each L-shaped portion 61 extends between opposed vertical portions 39, 40 of inner shell 21 (FIGS. 4 and 6), and the ends of each portion 61 about an inner surface of a respective vertical portion 39, 40. L-shaped portions 61 act as bracing members between the side walls of inner shell 21 and further rigidify the trolfer for vibration resistance.

As shown in the dash-dot lines in FIGS. 4 and 5, top wall 36 of inner shell 21 carries ballast 14 and tube sockets 13 for holding fluorescent tubes 17.

FIG. 7 shows lower panel 19 of unit 10 hingedly mounted on the troifer. As also illustrated in FIG. 1, lower panel 19 comprises a glass plate 65 mounted in a peripheral frame 66. One of the longitudinal side portions of frame 66 contains a pair of hinges 67 that are arcuate in shape and constructed for insertion through two pairs of aligned slots 68, one pair being in vertical portion 39 of inner shell 21 and the other pair being in a mounting strip 69 attached to the inner surface of vertical portion 39. Hinges 67 engage vertical portion 39 in hook fashion to hingedly mount lower panel 19 on the trofler. The opposite longitudinal side portion of frame 66 carries a pair of conventional latches indicated generally at 70, each of which extends through a slot (not shown) in another mounting strip 69 attached to the other vertical portion 40 of inner shell 21 thereby to detachably engage the mounting strip 69.

It has been found that, in sheet metal air-duct structures of the class including the herein disclosed structure (with particular reference to side passages 23 and 24,

0 leading to outlet openings 43), vibration noises arise primarily from vibration of the side walls of the structure in the jet-velocity zone which includes the region of the most restricted area (between the overlapping portions of wall sections 29 and 40) and the immediately adjacent downstream region (between 31, 40 and 42) through which air flows at jet velocity. This vibration includes movements of the side walls of the structure toward and away from each other as well as localized movements of the side wall members in directions generally parallel to each other. It has been found that stiffening members (also termed joining and bracing members) of the bracing or stiffness character of the previously described Z-shaped members 46 are substantially completely effective to damp out the noise-generating vibrations in the disclosed structure when placed generally within the noted jet-velocity zone (within which they are substantially completely located as disclosed) but are no more than partly effective when located a substantial distance outside of that zone.

In FIG. 6, four of the previously described Z-shaped joining and bracing members 46, located in the side passageways 23 and 24 (leading to outlet openings 43) are shown at the respective corners of the fixture near the extremities of these horizontally elongated side passageways, and additional ones are shown located between these extremities at a material distance therefrom to provide effective intermediate bracing between the shells 20 and 21 which comprise the sidewalls of the passageways. In the usual case, the flanges 41 and 42 of shell 21 and the flanges 32 and 33 of shell 20 provide sufficient stiflness such that intermediate bracing of these sidewall members is not required, but such bracing may be required for greater fixture lengths or when the sidewall members 20 and 21 are composed of very thin sheet material. When only two bracing and joining members 46 are used for each side passage between members 20 and 21, it is preferred that they be placed as shown near the ends of shell members 20 and 21 to fixedly join the shell members together at a gauged distance apart independent of end plates 22 and also to brace them against vibration. While the illustrated Z-shape of members 46 is preferred for use at the precise location illustrated because of the ease with which the problem can be solved of avoiding blockage of air flow in directions which are lateral to the general flow direction through the pasageways, other shapes of the bracing member can be used. Among them are a U-shape with the side arms or flanges contacting the shell members. The essential requirements of such a bracing member are that it is thick enough throughout to have. a.

high stiffness characteristic, that it includes two flanges which contact the respective shell members 20 and 21 and are fixed firmly thereto, as by spot welding, and that it further includes a cross flange which connects the shellcontacting flanges together.

While the expression trotfer as herein used is sometimes limited to meaning a light fixture which is a structure intended to have at least one electric lamp or other light source installed directly therein and fixed thereto as by at least one socket located in the structure and fixed thereto, that expression is herein used merely as a convenient term to be applied to structure of the character herein disclosed within which a light or a light fixture may be placed, irrespective of whether or not any light or light fixture is placed within that structure, since the invention is concerned primarily with the herein described structure which provides the disclosed air passage between the shells 2t} and 21 which is complete without using any of the inner space of the structure, which is the space within inner shell 21. By the use of such a structure, any electric-light emitters such as electric-light bulbs or fliuorescent tubes included within the inner space are not subjected to the cooling effect of direct contact with the air which is caused to flow through the air passage, which cooling effect is greatest when the air v being discharged comprises cooled air for the usual room-cooling or airconditioning purposes. This cooling effect may be disadvantageous to many types of light emitters but it is most pronounced for fluorescent tubes, which are readily cooled to such an extent that the amount or color composition, or both, of the emitted light is adversely affected to a great and readily observable degree.

By reference to FIG. 1, and to FIG 6, for example, it will be observed that the subject air-supply troffer, together with its light-access door or window 65 and 66, is a light and air structure which is flush-mounted with respect to the ceiling surface, within the ordinary meaning of the term flush-mounted, despite minor departures from a perfectly flush mounting such as are represented by the thickness of the usual metal flanges having their counterpart in flanges 32 and 33 shown in FIG. 6. It is a common requirement for a flush-mounted structure that the exposed surface portions thereof all be located generally in the same plane, with permissible departures from the state of being exactly coplanar being no more than a small or insignificant distance. In the subject air-supply trotfer and in any other practical air-supply troifer that distance is too small in relationship to conventional or practically usable side dimensions of the structure to accommodate sidewardly facing discharge slits r openings which are wide enough to provide a discharge opening large enough to discharge of more than a small fraction the ordinarily required air-flow rate at the highest air pressures ordinarily considered feasible. It is thus a practical requirement of a troffer of a feasible length that the air openings face directly downwardly from the ceiling, or nearly so, rather than sidewardly, at a flush-mounted airsupply. The most desirable direction of air flow from a ceiling-mounted fixture which supplies cooled or uncooled ventilating air is not directly downwardly, but is downwardly and sidewardly at a substantial acute angle to the vertical direction such as no less than 35 degrees and preferably greater, to thereby greatly relieve the common complaint of persons within air cooled spaces of air blowing directly down upon them, while at the same time providing improved distribution of the air currents by contact thereof with the walls of the room, and with each other when a number of air-supply fixtures are installed and by providing longer paths for the discharged air streams to broaden and lose velocity and temperature before impinging upon persons within the room or space being supplied with cooled air. A feature of the invention is that either of the downwardly facing slits or discharge openings 43 of the flush-mounted structure herein disclosed is arranged to provide the noted downwardly and laterally directed air streams of the said angular relationship to the vertical direction notwithstanding the fact that each of the openings 43 faces substantially directly downwardly. They so face because the bottom surfaces of the members defining them are opposite each other within substantially the same horizontal plane. The princlpal surfaces defining these openings 43 (see FIG. 6) are the lower surface of flanges 33 and 42 for one of them and of flanges 32 and 41 for the other.

There has thus been shown a combination ventilating and illuminating unit including a troifer which is compact, sturdy, and vibration-resistant. It is to be understood that the embodiment shown and described herein is merely illustrative of one of the many forms which the present invention may take in practice without departing from the scope of the invention as defined in the appended claims.

The invention claimed is:

1 A troifer for a combination ventilating and illuminating unit, said troifer comprising:

a trough-shaped outer shell having open ends;

a trough-shaped inner shell having open ends and disposed in nesting relation to said outer shell to define air passages therebetween,

each shell having a substantially rectangular top wall,

a pair of inclined portions each extending downwardly and outwardly from a first pair of respective opposite side edges of said rectangular top wall, and a pair of vertical portions each extending downwardly from the lower extremity of a respective inclined portion;

a pair of channel-shaped spacing members each located ad acent a second pair of respective opposite side edges of each of said rectangular top walls of each of said shells between the top walls of said inner and outer shells;

Z-shaped spacing members between said shells,

each Z-shaped spacing member having a first flange abutting a respective vertical portion of said inner shell, a second flange abutting a respective vertical portion of said outer shell, and a Web extending between said first and second flanges;

a pair of end plates each located at a respective opposite end of said shells,

each end plate having a peripheral configuration conforming substantially to the cross-sectional configuration of said outer shell, and

each end plate having an inwardly extending peripheral flange overlapping the top wall, the inclined portions and the vertical portions of said outer shell to close the open ends of the inner and outer shells, whereby the end plates seal off the air passage defined between the nested inner and outer shells;

means on said inner shell for accommodating a lighting element;

and means on said outer shell for receiving an air supply such that air introduced into the air passage volume between the nested inner and outer shells is directed outwardly and downwardly to exit from the troffer.

2. A troffer as recited in claim 1 wherein:

the upper extremity of each vertical portion on said inner shell is lower than the upper extremity on the adjacent vertical portion of the outer shell;

the lower extremity of each vertical portion on said inner shell is lower than the lower extremity on the adjacent vertical portion of the outer shell;

the upper and lower extremities of said first flange on each of said Z-shaped spacing members extend no further than the upper and lower extremities respectively of the abutting vertical portion on said inner shell;

the upper and lower extremities of said second flange on each of said Z-shaped spacing members extend no further than the upper and lower extremities respec- 7 tively of the abutting vertical portion on said outer shell;

and said outer shell has a second pair of inclined portions, each portion extending downwardly and outwardly from the lower extremity of a respective vertical portion on the outer shell.

3. A trolfer as recited in claim 2 and further comprisa pair of substantially horizontal flanges each extending in an opposite outward direction from the lower extremities of a respective vertical portion on said inner shell,

References Cited in the file of this patent UNITED STATES PATENTS Kurth Nov. 15, 1960 Falk July 11, 1961 Geocaris Nov. 28, 1961 

